This is just a personal pet peeve that I see more and more programs doing. It is typically done by programmers that either didn't have time to come up with a decent icon or didn't know how to change it within Visual Studio. When I see programs that use defaults in their resources like 'Form1' and such, it just gives me the impression of sloppy coding, even if I haven't seen the underlying code.
Sure, you could use a resource hacker program to insert your own icons but I wish more programmers would not use the default icon sets.
Here is an example of what I am talking about if this isn't making any sense to you: